JP3301811B2 - Bicycle with electric motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a drive system driven by a human power and a drive system driven by an electric motor in parallel, and controls the drive power of the electric motor in response to a change in the drive power (hereinafter referred to as "pedal force"). The present invention relates to a bicycle with an electric motor as described above.

[0002]

2. Description of the Related Art It is known that a pedaling force is detected and the driving force of an electric motor is controlled in accordance with the magnitude of the pedaling force (JP-A-50-125438, JP-A-56-76590).
And JP-A-2-74491. That is, when the load of human power is large, the driving force of the electric motor is also increased to reduce the load of human power.

[0003] Here, since a manual driving force (pedal force) is input from a crank pedal, it changes with a cycle of a half rotation of a crankshaft. Therefore, when the crank pedal comes to the top dead center or the bottom dead center, the pedaling force becomes almost zero.

[0004]

As described above, in the conventional control method, the motor output greatly fluctuates with the change in the pedaling force.
Every time the pedaling force becomes zero, the output of the motor also becomes zero, and the motor output periodically fluctuates with the pedaling force. For this reason, the fluctuation range of the motor output increases, and the maximum output of the motor also increases. Therefore, it is necessary to increase the motor capacity and the capacity of the control device. As a result, there arises a problem that the motor and the control device are enlarged.

[0005] In a secondary battery such as a lead battery, when the discharge current is small and constant, the dischargeable power, that is, the discharge capacity increases. For this reason, when the discharge current of the battery periodically fluctuates greatly with the fluctuation of the pedaling force as described above, the discharge capacity of the battery also decreases, which adversely affects the life of the battery.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to reduce the size and capacity of a motor and a control device when controlling a motor output in accordance with a pedaling force. It is an object of the present invention to provide a bicycle with an electric motor that can increase the dischargeable capacity of the battery and extend the battery life.

[0007]

According to the present invention, an object of the present invention is to provide a bicycle with an electric motor in which a human-powered drive system and an electric drive system are provided in parallel, and the output of the electric drive system is controlled in response to a change in treading force due to human power. a pedal force detection means for detecting a pedal effort, C
A motor output calculating means for determining a constant output of the electric motor over the next one cycle based on the measured value within one cycle of the pedaling force formed by the PU and obtained at every fixed time dt ; And a power control means for generating the electric power.

[0008] The motor output calculation means is one cycle of the pedal force fluctuation.
The maximum value of the pedaling force can be used as the measurement value in the above.
The measured value is the time of the pedaling force during one cycle.
All integral values can be used.

[0009]

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a power system diagram thereof, FIG. 3 is a block diagram showing functions of the controller, FIG. 4 is an operation explanatory diagram, and FIG. is there.

In FIG. 1, reference numeral 10 denotes a main frame, which extends rearward from a head pipe 12 obliquely downward and rearward.
4 axles. A seat tube 16 is fixed substantially perpendicular to the main frame 10, and a seat post 20 for supporting a saddle 18 is fixed to an upper end of the seat tube 16.

A lower portion of the seat tube 16 is formed with a cylindrical portion 16a opened downward, and a permanent magnet type DC electric motor 22 is accommodated therein. A power unit 24 is fixed to a lower end of the seat tube 16. The power unit 24 includes a bottom bracket case (hereinafter referred to as a BB case) 26 and a rear stay 28 extending rearward from the BB case 26. The rear wheel 14 is fixed to the rear end of the rear stay 28. The drive shaft 30 (see FIG. 2) is inserted through the right rear stay 28.

A crankshaft 32 is inserted through the BB case 26 of the power unit 24, and a crank 34 is fixed to both ends thereof. The crank 34 has a crank pedal 36,
36 are attached.

The left end of the axle 38 of the rear wheel 14 is fixed to an end plate 28a fixed to the left rear stay 28,
The right end of the axle 38 is fixed to a bevel gear case (not shown) fixed to the right rear stay 28. Axle 38
A rotatable hub (not shown) is rotatably held therein. The rotation of the drive shaft 30 is transmitted to the hub via a bevel gear mechanism and a one-way clutch 42 (FIG. 2).

The power unit 24 transmits the rotation of the crankshaft 32 to the drive shaft 30 via a one-way clutch 44 (FIG. 2).
Bevel gears (not shown) to be transmitted to the vehicle. A planetary gear mechanism is interposed between the crankshaft 32 and the drive shaft 30.

In this planetary gear mechanism, pedaling force is input from the planetary gear, and pedaling force is output to the drive shaft 30 from the ring gear. The pedaling force F is detected by detecting a torque applied to the central sun gear by a potentiometer 46 as a pedaling force detecting means. Motor 2
2 is transmitted to the drive shaft 30 via the one-way clutch 48 and the speed reducer 50.

In FIG. 1, reference numeral 52 denotes a rechargeable battery such as a lead battery, and reference numeral 54 denotes a controller, which is accommodated between the head pipe 12 and the seat tube 16 of the main frame 10. In FIG. 1, reference numeral 56 denotes a vehicle speed sensor for obtaining the vehicle speed S from the rotation speed of the crankshaft 32.

The pedal force F detected by the potentiometer 46 control - are input to La 54, this controller - La 54 controls the motor current to generate a motor output or motor torque T _M on the basis of the pedal force F.

The controller 54 is configured as shown in FIG. The motor 22 and the battery 52 form a closed circuit together with the switching circuit 60, and this closed circuit becomes the main circuit 62. The switching circuit is composed of, for example, a MOS-FET. A flywheel diode 64 is connected to the motor 22 in parallel, and a shunt 66 for detecting current is attached to the main circuit 62.

Reference numeral 68 denotes a CPU, and 68a denotes a memory. C
The PU 68 outputs a command value i of the output (torque) T _M of the motor 22 based on the pedaling force F, the vehicle speed S, and the like. That is, the command value i is output so that the output (torque) T _M of the motor 22 is output at a constant value in the next cycle using the measured value within one cycle of the pedaling force F. Further, when the rotation of the crankshaft 32 stops or becomes lower than a certain speed, or when the vehicle speed S becomes higher than a certain speed, the motor output T _M may be limited to limit the vehicle speed S.

A gate circuit 70 outputs a gate signal g whose duty ratio changes in accordance with a command value i supplied from the CPU 68. That is, when the command value i increases the motor output T _M , the (on time) of the gate signal g
The value of / (off time + on time) (duty) is increased.

The gate signal g output from the gate circuit 70 based on the command value i is sent to the switching element of the switching circuit 60 to selectively turn on / off the switching element.
Turn off.

In FIG. 3, reference numeral 72 denotes a pedal force increase / decrease detecting means for detecting a time derivative dF / dt of the pedal force F. In the treading force increase / decrease detecting means 72, as shown in FIG. 4, the difference between the measured values of the treading force F detected at every time dt by the potentiometer 46, that is, the previously detected measured value (previous value) F (t−d
t) and the sign of the difference between the next detected value (the next value) F (t) and the flag are output. Therefore, the sign of the difference is + while the measured value of the pedaling force F increases, and becomes-while the measured value of the pedaling force F decreases, and becomes 0 if there is no change in the difference. Changes from-to + when 0 changes from + to +, and + when the difference changes from 0 to-.
Changes from-to-.

In FIG. 3, reference numeral 74 denotes a maximum value detecting means, which stores the treading force F obtained immediately before the flag shown in FIG. 4 changes from + to-as a local maximum value. The symbol “４” in the column for rewriting the maximum tread force in FIG. 4 indicates the timing at which the maximum value is obtained and the memory is rewritten.

[0024] 76 is a motor output (T _M) operation means, by using the maximum value F _M of force F obtained, calculates the output T _M to be generated by the motor 22 within this next one cycle. Here, the motor output T _M is set to a constant value within this one cycle. For example, to the motor output T _M which is proportional to the maximum value F _M, it may be determined motor output T _M with a predetermined constant relation.

Reference numeral 78 denotes output control means for outputting a command value i for causing the motor 22 to continuously generate a constant motor output T _M obtained by the motor output calculation means 76 during the next one cycle. Reference numeral 80 denotes an auxiliary stop determining means, and the pedaling force F
Is determined to be equal to or less than the pedaling force reference value F ₀ , and if this period (time period) is equal to or greater than a preset maximum limit t _{M, the} crankshaft 32 is determined to be stopped and the assist by the motor 22 is stopped. That is, the motor output T _{M is set} to zero.

Next, the operation will be described with reference to FIG. First C
The PU 68 sets the flag to + (step 100), sets the pedaling force reference value F ₀ (step 102), and sets the longest limit t _M.
Set (step 104), the pedal force maxima F _M is initialized (step 106), performs other initialization process. Then, the treading force measurement is started, and the treading force measurement value is read every fixed time (measurement cycle) dt (step 108).

The auxiliary stop determining means 80 determines the pedaling force F (the next value).
Is compared with the pedal effort reference value F ₀ (step 110), and F> F ₀
If it is, reset the time counter to 0 (step 11).
2) Continue counting the counter. The count value of this counter (corresponding to the time period t) is the longest limit t
_If it is larger than _M (t> t _M ) (step 114), it is determined that the crankshaft 32 is stopped and the assist by the motor 22 is stopped (step 116), and the control is ended (step 11).
8).

If the count value (t) is smaller than the longest limit t _M (t <t _M ), the treading force increase / decrease detecting means 72 obtains the difference between the treading force measured values dt (step 120), and this difference is increasing. If so, it is determined that the difference is positive (step 122), and it is checked whether the difference matches the flag set in step 100 (step 124). In this case, since they match, the process returns to step 110. If the flags do not match, the flag is rewritten to plus (step 126), and the process returns to step 110 .

If the measured value of the pedaling force is decreasing, the difference in the pedaling force during the measurement cycle dt is negative (steps 120 and 12).
8) It is checked whether or not it matches the last flag stored in the memory (step 130). If they match, the process returns to step 110. If they do not match, it means that the flag in FIG. 4 has changed from + to-, so the flag is rewritten to minus (step 132), and the immediately preceding pedaling force F is reduced. Set to the maximum value. Then, the maximum value in the memory is rewritten with the new maximum value (step 134), and step 11 is executed.
Return to 0).

[0030] Although this embodiment obtains the motor output T _M by maxima F _M of the pedal effort, the present invention is not limited thereto. For example, the motor output T _M may be obtained using an integral value of the time of the pedaling force F during one cycle, or using an average value of the pedaling force within one cycle . Further, the motor output T _M may be increased or decreased according to the rotation speed of the crankshaft 32 or the vehicle speed S. For example, when the vehicle speed S exceeds a certain value, the motor output T
_M may be reduced.

[0031]

According to the first aspect of the present invention, as described above, the CPU
Thus, a constant motor output is set over the next one cycle based on the measured value within one cycle of the pedaling force obtained every fixed time dt , so that the motor output is constant within one cycle of the pedaling force. Thus, the size of the motor can be reduced. If the motor output is reduced, the control device can be reduced in capacity and size. Also, since the fluctuation of the discharge current of the battery becomes small,
It is possible to increase the discharge capacity of the battery and prolong the battery life.

Here, the maximum value of the pedaling force is used as the measured value.
(Claim 2). Also, as the measured value,
It is also possible to use the integral value of the time of treading force during one cycle.
(Claim 3).

[Brief description of the drawings]

FIG. 1 is a side view of one embodiment of the present invention.

Fig. 2 Power system diagram

FIG. 3 is a block diagram showing functions of a controller.

FIG. 4 is an explanatory diagram of an operation.

FIG. 5 is an operation flowchart.

[Explanation of symbols]

Reference Signs List 14 rear wheel 22 electric motor 36 crank pedal 46 potentiometer 54 as treading force detecting means 54 controller 68 CPU 72 treading force increase / decrease detecting means 74 treading force maximum value detecting means 76 motor output calculating means 78 output control means F treading force T _M motor output

Continuation of the front page (56) References JP-A-4-321482 (JP, A) JP-A-1-314685 (JP, A) JP-A-2-74491 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) B62M 23/02

Claims (3)

(57) [Claims] 1. A stepping force detecting means for detecting a stepping force in a bicycle with an electric motor which is provided with a manpower driving system and an electric driving system in parallel and controls the output of the electric driving system in response to a change in the stepping force due to the manpower. A fixed time d formed by the CPU
motor output calculating means for determining a constant electric motor output over the next one cycle based on the measured value within one cycle of the pedaling force obtained for each t; output control means for generating the obtained motor output; A bicycle with an electric motor, comprising: 2. The motor output calculating means according to claim 1, further comprising:
For determining the electric motor output for the next one cycle based on the
Item 1. A bicycle with an electric motor according to item 1. 3. The motor output calculating means includes a pedaling force for one cycle.
Based on the integral value for the
The bicycle with an electric motor according to claim 1, wherein the bicycle determines the motor output.